Wow - you have had a lot to deal with in a short period of time! May I suggest that you take a big step back, and give yourself time to grieve? Because that is what you need to do - you need to grieve the loss of the way things used to be. All of us go through that after ostomy surgery, but you have had a double whammy. So be gentle with yourself, and give yourself some time. You need to remember that none of this was your fault. I know you "know" that, but do you truly believe it? We humans are so fond of finding answers to questions that sometimes we will find fault with ourselves. Easier to think that we are to blame than to have no answer at all. So, take stock of your thoughts, and if you are harbouring feelings of guilt, do whatever you need to do to let those go. You will have good days and bad days throughout this journey. Give yourself permission to have bad days; even wallow for awhile if that's what you need to do. But then ask yourself how you want to live the rest of your life, and do what you need to do to get on with the rest of your life. You don't need anyone's permission to be who you are, and to live your life in the way that you want. Period.
Push yourself out of the sadness rut. Get outside every single day for "mindful " walks. By that I mean observe what is going on around you, rather than what is going on in your head. Notice, without judgment, the temperature, the sun or cloud, the roughness of the tree bark, the unevenness of the ground you are walking on, the birdsong you can hear, the colour differentiations in the house bricks - anything that gets you out of your head. You already know what's going on in your head, so let that go for awhile, every day. Make a point of reminding yourself, every single day, of what you are grateful for. Write it down, maybe in a gratitude journal. Do you have clean air to breathe, clean water to drink? Not everyone in this world has that. Do you have family and friends who love you? Not everyone does. We all tend to take a lot for granted; during times we are grieving, we need to remind ourselves of what we lucky to have. Cupcake, this routine won't change things overnight for you, but it does work. This is what I did after my cancer diagnosis and treatment, and ostomy surgery. It helped me a lot.
You will need to arm yourself with knowledge. It is the most powerful tool in your toolbox. So talk to your doctors, check out (reputable!) internet sources, and join up with groups that can help. You have taken that step by reaching out to this group - good for you! Keep searching until you get the answers you need. Accurate information is your pathway out of the maze.
And finally, you have to address what you are looking for in a partner. You said that you have had mostly good experiences so far, so that tells me that you have been able to find partners who are not so shallow that they would reject you because of your ostomy. Let that inform future choices. Human beings are on a continuum, ranging from shallow to deep, and everything in between. Look towards the deeper end. On this site, you will hear people who have had horrible experiences with intimate partners, and you will hear people who haven't had bad experiences at all. Look in the deep end. There are lots of people of both genders (and LGBTQ!) who are mature enough emotionally to look beyond the superficial and see the real person. They are all in the deep end.
Above all, Cupcake, don't give up hope. I can hear the sadness in your post, and although our situations are different, I will tell you that it can get better. One of the silver linings of your experience is that it has likely made you more compassionate toward others, especially toward people who are struggling in life. Let that part of you grow. When you do that, you are swimming toward the deep end, where you will meet so many like minded people. One day, you will be offering support to someone else on this site, because of your life experiences. Keep us posted on how you are doing.